Slip ring assembly



June 15, 1943. H, G. FRENCH v SLIP RING ASSEMBLY Filed May 27 fwflv Z ////////f/Z/ZZZZA 2 we U lllllllllllll Inventor- Henna (3. French,

His Attorney Patented June 15, 1943 SLIP RING ASSEMBLY Henry G. French, Schenectady, N. Y., assignor to General Electric Company, a corporation of New York Application May 27, 1942, Serial No. 444,743

Claims.

My invention relates to slip ring constructions such as are used for current collecting purposes on dynamoelectric machines.

An object of my invention is to provide an improved and simplified slip ring assembly wherein conductors connected to the slip rings are prevented from contacting slip rings to which they are not connected and are prevented from being exposed to the inner bore of the assembly.

Further objects and advantages of my invention will become apparent and my invention will be better understood from the following description referring to the accompanying drawing, and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming part of this specification.

In the drawing Fig. l is a longitudinal sectional View through a slip ring assembly embodying my invention; Fig. 2 is a longitudinal sectional view, taken along line 2-2 of Fig. 4, of another embodiment of my improved slip ring assembly; Fig. 3 is a longitudinal sectional View of a part of the assembly shown in Fig. 2, taken along line 3-3 of Fig. 4; and Fig. 4 is an end view of the slip ring assembly shown in Fig. 2.

It has been found that current collecting slip ring assemblies may not provide uniform electrical voltage breakdown characteristics when molded insulation is used about certain parts of the slip rings due to the fact that the position of the conductor leads connected to the slip rings cannot be controlled with suflicient accuracy during the molding operation. At times the conductor lead may become pressed to the inner surface of the bore through the inner insulating sleeve or may be pressed into close contact with a slip ring to which it is not connected, so that even though no breakdown will occur under high potential tests when the assembly is new, corona and other electrical discharges may cause the insulation to deteriorate adjacent that portion of the conductor which is near another electrically conductive element. This aging of the slip ring assembly causes an eventual breakdown requiring a new slip ring assembly to be substituted on the machine. In order to overcome this difficulty my improved construction utilizes a separate insulating element for each of the slip rings and thereby insures against the possibility of contact between a slip ring and a conductor which are not electrically connected together. My assembly also provides an inner sleeve of insulating material separate from the insulation arranged about the conductor leads to assure against contact between any insulator lead and an electrically conductive shaft on which the slip ring assembly is mounted.

In Fig. 1 is shown a slip ring assembly including a plurality of axially spaced apart slip rings l0 and H of electrically conductive material. The slip ring I0 is mounted on an insulating ring element [2 and is electrically connected to a lead conductor l3. The slip ring II is provided with a lead conductor l4 electrically connected thereto and arranged substantially electrical degrees away from the lead conductor I3. This slip ring 10, insulating element l2, and conductor l3 are arranged in a mold in axially spaced apart relationship from the slip ring I l, and a hardenable plastic insulating material I5 is molded about these two parts of the slip ring assembly providing an insulating support for the slip ring ll separate from the insulating element l2 for the slip ring IU. With this arrangement the ends of the conductor leads l3 and I4 which are not connected to the slip rings Ill and II are arranged to extend to the exterior of the insulating member l5. The inner bore of the insulating member I5 is slightly tapered such that one and I6 thereof is formed on a slightly smaller diameter than the other end I! and a separate insulating sleeve [8 having a complementary tapered outer surface is arranged in engagement with the inner tapered surface of the insulating member l5 and is secured thereto in any suitable manner, as by a cemented bond. The insulating sleeve I8 is provided with an inner bore l9 which may be cylindrical or tapered for mounting on any suitable supporting shaft or spindle. With this construction the insulating member l2 assures against contact between the slip ring H1 and the conductor lead l4, and the inner insulating sleeve I8 assures against exposure of either of the leads l3 or I4 to the inner bore I?! of the inner insulating element l8 and thereby assures against the undesirable breakdown of the insulating elements between the conductor leads and slip rings or the shaft upon which the assembly is mounted.

In the construction shown in Figs. 2, 3 and 4 a slip ring 2|] is electrically connected to a conductor lead 2| and is secured on an insulating sleeve member 22 by an insulating ring 23 mounted on an end of the sleeve 22 and secured thereto in any suitable manner, as by a cemented bond. A second electrically conductive slip ring 24 is electrically connected to a conductor lead 25 and is mounted on a separate insulating member 26, which is provided with a section having an outer tapered surface 21 arranged in engagement with a complementary inner tapered surface 28 on the insulating member 22. The inner end of the insulating member 22 is arranged in engagement with an edge of the slip ring 24 and a shoulder 29 formed on the insulating member 26, thus securing the ring 24 in position on the sleeve 26, and the two insulating members 22 and 26 are secured together in any suitable manner, as by a cemented bond. The insulating member 22 is formed with an axially extending substantially semicylindrical groove 30 on the inner surface thereof substantially 180 electrical degrees from the conductor lead 2|, and the insulating member 26 is formed with an axially extending substantially semicylindrical groove 3| on the outer surface thereof. These two grooves are arranged in alignment to provide a substantially cylindrical opening between the insulating elements 22 and 2E, and an insulating tube 32 is arranged about the conductor lead 25 within the cylindrical passage formed by the grooves 30 and 3|. The insulating element 26 is formed as a sleeve which extends substantially the full length of the slip ring assembly and is provided with an inner bore 33 which is adapted to be arranged about a shaft or spindle for supporting the assembly. With this construction each of the slip rings 2!! and 24 is provided with a separate insulating supporting member and each of the conductor leads 2i and 25 also is provided with an insulating element separate from that of the other lead which assures against contact of the lead conductors with the slip rings to which they are not connected. The provision of the insulating tube or sleeve 32 about the conductor lead 25 and the arrangement of the sleeve portion of the insulating member 26 within the insulating member 22 assures against exposure of any of the leads to the inner bore 33 of the inner insulating element 28. This construction assures against breakdown between any of the conductor leads and adjacent conductive members due to aging of the insulating material because of the proximity of the conductor leads to an electrically conductive element having a different electrical potential from the leads.

While I have illustrated and described particular embodiments of my invention, modifications thereof will occur to those skilled in the art. I desire it to be understood, therefore, that my invention is not to be limited to the particular arrangements disclosed, and I intend in the appended claims to cover all modifications which do not depart from the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A slip ring assembly including a plurality of electrically conductive slip rings, concentric and partially axially coextensive separate insulating elements for supporting each of said rings, electrical conductors connected one to each of said rings and extending through said insulating elements to the exterior thereof, and means including said insulating elements arranged about said electrical conductors for preventing contact of said conductors with any of said rings other than the rings to which said conductors are connected or exposure thereof to the inner bore of the inner of said insulating elements.

2. A slip ring assembly including a plurality of electrically conductive slip rings, substantially concentric eparate insulating elements for supporting each of said slip rings, electrical conductors connected one to each of said slip rings and extending through said insulating elements to the exterior thereof, and means including said insulating elements arranged about said electrical conductors and a separate insulating sleeve element to which said insulating elements are secured for preventing contact of said conductors with any of said rings other than the rings to which said conductors are connected or exposure thereof to the inner bore of the inner of said insulating elements.

3. A slip ring assembly including a plurality of electrically conductive slip rings, concentric and partially axially coextensive separate insulating elements for supporting each of said slip rings, electrical conductors connected one to each of said slip rings and extending through said insulating elements to the exterior thereof, and means including said insulating elements arranged about said electrical conductors and a separate insulating sleeve element to which said insulating elements are secured for preventing contact of said conductors with any of said rings other than the rings to which said conductors are connected or exposure thereof to the inner bore of the inner of said insulating elements.

4. A slip ring assembly including a plurality of electrically conductive slip rings axially spaced apart, electrical conductors connected one to each of said slip rings, concentric and partially axially coextensive separate insulating elements for each of said rings molded about said conductors, one of said insulating elements forming a sleeve extending substantially the full length of said assembly, and means including said insulating elements about said electrical conductors for preventing contact of said conductors with any of said rings other than the rings to which said conductors are connected or exposure thereof to the inner bore of said sleeve insulating element.

5. A slip ring assembly including a plurality of electrically conductive slip rings axially spaced apart, concentric and partially axially coexten sive separate insulating elements for supporting each of said rings, one of said insulating elements forming a sleeve extending substantially the full length of said assembly, electrical conductors connected one to each of said rings and extending through said insulating elements to the exterior thereof, and means including said insulating elements arranged about said electrical conductors for preventing contact of said conductors with any of said rings other than the rings to which said conductors are connected or exposure thereof to the inner bore of the inner of said insulating elements.

HENRY G. FRENCH. 

